[Bug c++/71957] New: Invalid code generation with function static objects

["sebastian dot huber at embedded-brains dot de" <gcc-bugzilla at gcc dot gnu dot org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=71957

            Bug ID: 71957
           Summary: Invalid code generation with function static objects
           Product: gcc
           Version: 6.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: sebastian.huber@embedded-brains.de
  Target Milestone: ---

The following test case produces wrong code with GCC 6. The problem is at least
visible on x86, ARM, SPARC and PowerPC.

class A {
public:
  A(int);
};

template <typename T> class B {
public:
  virtual void* h(int) = 0;
};

template <typename T> class C : public B<T> {
public:
  explicit C(int);
  void* h(int);
};

C<A>& g(void);

class D : public A {
  static void* f(int);
};

void* D::f(int k) {
  B<D>& j = (reinterpret_cast<C<D>&>(g()));
  return j.h(k);
}

int f(void);

C<A>& g(void) {
  static C<A> i(f());
  return i;
}

g++ -Wfatal-errors -Wall -Wextra -S -O3 -fno-exceptions test.cc -o-
        .file   "test.cc"
        .text
        .align 2
        .p2align 4,,15
        .globl  _ZN1D1fEi
        .type   _ZN1D1fEi, @function
_ZN1D1fEi:
.LFB0:
        .cfi_startproc
        subq    $8, %rsp
        .cfi_def_cfa_offset 16
        movl    $_ZGVZ1gvE1i, %edi
        movzbl  _ZGVZ1gvE1i(%rip), %eax
        call    __cxa_guard_acquire

<-- ERROR: It must check the return value of __cxa_guard_acquire()

        call    _Z1fv
        movl    $_ZZ1gvE1i, %edi
        movl    %eax, %esi
        call    _ZN1CI1AEC1Ei
        movl    $_ZGVZ1gvE1i, %edi
        call    __cxa_guard_release

<-- ERROR Invalid function return

        .cfi_endproc
.LFE0:
        .size   _ZN1D1fEi, .-_ZN1D1fEi
        .p2align 4,,15
        .globl  _Z1gv
        .type   _Z1gv, @function
_Z1gv:
.LFB1:
        .cfi_startproc
        movzbl  _ZGVZ1gvE1i(%rip), %eax
        testb   %al, %al
        je      .L15
        movl    $_ZZ1gvE1i, %eax
        ret
        .p2align 4,,10
        .p2align 3
.L15:
        subq    $8, %rsp
        .cfi_def_cfa_offset 16
        movl    $_ZGVZ1gvE1i, %edi
        call    __cxa_guard_acquire
        testl   %eax, %eax
        je      .L5
        call    _Z1fv
        movl    $_ZZ1gvE1i, %edi
        movl    %eax, %esi
        call    _ZN1CI1AEC1Ei
        movl    $_ZGVZ1gvE1i, %edi
        call    __cxa_guard_release
.L5:
        movl    $_ZZ1gvE1i, %eax
        addq    $8, %rsp
        .cfi_def_cfa_offset 8
        ret
        .cfi_endproc
.LFE1:
        .size   _Z1gv, .-_Z1gv
        .local  _ZGVZ1gvE1i
        .comm   _ZGVZ1gvE1i,8,8
        .local  _ZZ1gvE1i
        .comm   _ZZ1gvE1i,8,8
        .ident  "GCC: (GNU) 6.1.1 20160705 [gcc-6-branch revision
fcd04db:3fed107:ebf5486fa49b6660091b549d17e945f63e698eac]"
        .section        .note.GNU-stack,"",@progbits